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Clinical Outcomes & Statistics of Knee Replacement

Written by Samuel Greengard
| Published on February 18, 2015Medically Reviewed by George Krucik, MD, MBA
on February 18, 2015

According to the American Academy of Orthopedic Surgeons, 90 percent of people who
have a knee replacement have a lot less pain. Most of these people are able to
perform daily activities and stay active. In many cases, they’re able to resume
activities like golf and walking that their arthritic pain made them give up
years ago.

A total
knee replacement (TKR) is also known as a
total knee arthroplasty (TKA). It relies on a mechanical implant to replace
your actual knee.

Success Rates

The device usually lasts well over a decade. The procedure is being
used more and more for younger people with osteoarthritis (OA) and other
degenerative knee conditions. About 85 percent of artificial knees still
work after 20 years. Their endurance is one reason that this procedure is so
popular.

Most people who undergo a knee replacement are between the ages
of 50 and 80. The average age is about 70. About 60 percent of the recipients
are women. The procedure has a high success rate and is considered very safe
and effective.

Safety and Complications

The safety of TKRs is well documented. According to the American Academy of Orthopedic Surgeons, “Serious complications,
such as knee joint infection, occur in fewer than 2 percent of patients.” Blood
clots can be a risk, as they are with all orthopedic procedures, but the risk
is low. Using a blood thinner or other common preventative measures can help
decrease the risk of a pulmonary embolism. A pulmonary embolism is the worst
potential complication of a blood clot.

Did You Know?

Ninety percent of total knee replacements still work after 10 years.

One study found that only 1.2 percent of people getting
a TKR were hospitalized for blood clots within 90 days of surgery. Men over the
age of 70 have the highest risk of blood clots. Cases of osteolysis — when plastic
or metal fragments are released from the knee implant into the body and cause
inflammation — are also uncommon.

Your implant won’t last forever. Over time, the metal and
plastic parts wear out. People who are overweight or take part in high impact
activities are more likely to experience problems with the mechanical knee
implant.

Knee implants can come loose in rare cases. This is most likely
to happen at the start of rehabilitation, typically a few days after surgery. It’s
also rare for the device to malfunction. This is usually caused by a traumatic
injury.

People
often experience pain and require a revision surgery when an implant fails or
osteolysis occurs. About 10 percent of patients require a revision within 10
years. This involves the replacement of worn components with new prosthetics.

Positive Outcomes

A successful TKR or partial knee replacement (PKR) typically leads to a higher quality of
life, less pain, and better mobility. One study that examined 181 patients found that pain
scores decreased significantly after surgery. The people in the study who had
undergone a TKR also had improved range of motion of their knees.

Another 2011 study conducted at the University of Bremen in Germany found that
those who undergo a TKR for OA are able to be much more physically active
within a year of surgery. The study’s authors noted that a TKR “offers profound
improvements of physical activity for the majority of patients.”

Spend some time reading through this guide if you’re considering
a knee replacement. You should also check manufacturers’ websites and listen to
the testimonials of others who have received knee replacements. It could help
you have a smooth experience with knee replacement.

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